So I sent my To2 file to trimble centerpoint to get it post processed and they sent me back coordinates in ITRF2014. I use wgs84. How can I convert that coordinate to wgs84? Supposedly I hear they are supposed to be nearly the same thing but I got the?ÿProcessing Results
ITRF2014 at Epoch 2018.59
17d15'16.43539"
89d00'1.31074"
I was able to convert them using google earth.
16Q 287328.48 mE
1908818.19 mN
Is that an accurate conversion? Is there a better way to convert it?
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Sorry to reply with a non-answer, but why would a surveyor want/use WGS84??ÿ ITRF or a version of NAD83 seem more useful, but maybe you're working for the Department of Defense?
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What do you mean by WGS84? There are multiple realizations of WGS84, some are nearly the same as ITRF, earlier realizations were not quite. The epoch date for WGS84 matters.?ÿ
Does Belize have a "standard" datum in use? They used to be on NAD27, did they go to NAD83 or some flavor of WGS84?
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I am not working for Department of Defense. I am in Belize and when I started surveying WGS84 sounded like the way to go, and its easy to use in Google Earth. But I am new to this so mabe I need to switch over. Which ITRF or NAD 83 would you recommend for Belize?
http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html
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http://www.earthpoint.us/StatePlane.aspx
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Try one of these....
http://www.movable-type.co.uk/scripts/latlong-utm-mgrs.html
I just found this one and it works better for what I need it.
WGS84 makes some more sense given your location - I was doing the American thing where we assume everyone is American, but to answer your question about what you ought to be using: it depends.?ÿ Most coordinate systems specify the datum they're expecting for inputs (e.g. UTM 16N appears to use WGS84)... In the U.S. most NGS benchmarks and control points are publish values from some iteration of NAD83, so that's usually what we're using.?ÿ ?ÿ ?ÿ
I only use WGS84 and am pleased with the results of being consistent and repeatable.
Create my own control stations from TxDOT downloads without any scale corrections and everything matches with my TS direct readings.
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I always thought that the appropriate coordinate system to use was the one your organization or your client specifies. As Mr Hamilton writes above, there are a number of WGS84 versions. The versions are officially designated with a GPS week designation indicating at what date they were aligned to be consistent with ITRF.
As you indicate you work in Belize, are you aware of SIRGAS? If not see:?ÿ http://www.sirgas.org/fileadmin/docs/Boletines/Cioce_et_al_2018_SIRGAS_UN_Workshop_GNSS_Argentina.pdf
This is a regional implementation of the ITRF. Lots of good details available through the SIRGAS home page.
Given that you indicate you use your survey work in association with Google Earth, what sort of positional accuracy do you need in your work?
In any event, good luck.?ÿ
DMM
I only start with WGS84(or ITRF) because its the genesis of the GPS signal.?ÿ All the post processing after that is just a more highly constrained network based upon the regional(continental or country level)?ÿ and even smaller local areas (State plane, MilGrid, custom...)?ÿ What software are you using to process you data??ÿ This should be a simple programatic based function to get you to your final results.?ÿ
I am not working for Department of Defense. I am in Belize and when I started surveying WGS84 sounded like the way to go, and its easy to use in Google Earth. But I am new to this so mabe I need to switch over. Which ITRF or NAD 83 would you recommend for Belize?
You definitely don't want to use NAD83 for Belize, as it's not in the same reference frame.
What do you mean by WGS84? There are multiple realizations of WGS84, some are nearly the same as ITRF, earlier realizations were not quite. The epoch date for WGS84 matters.?ÿ
Does Belize have a "standard" datum in use? They used to be on NAD27, did they go to NAD83 or some flavor of WGS84?
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As far as I know then Belize is still on NAD27. I use autocad c3d. I haven't been able to check the epoch date for the coordinate version that autocad uses as utm wgs84, except for epsg code 32616.
FWIW,
This shows the various ??Versions? of WGS84.
BTW, the WGS84 Standardization document is here:?ÿ http://earth-info.nga.mil/GandG/publications/NGA_STND_0036_1_0_0_WGS84/NGA.STND.0036_1.0.0_WGS84.pdf
Lots of good details and maths. Not anything specific to Belize that I could find.
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Belize does not participate in Sirgas, at least not that I know of.?ÿ
Yes. I do not see any mention of Belize??s involvement.
There is a SIRGAS site in Belize (unless my knowledge of Central American geography is wrong). See:?ÿ http://www.sirgas.org/fileadmin/docs/Boletines/Bol17/Mattioli_et_al_COCONet.pdf
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The only transformation I've seen for NAD27 in Belize is the regional one defined by DMA/NIMA/NGA in 1987. It also covers Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua. The parameters are (copied from Cliff Mugnier's article on Belize?ÿ(PDF)):?ÿ
From NAD27 To WGS84 is: ??X = 0 m ?ñ8 m, ??Y = +125 m ?ñ3 m, ??Z = +194 m ?ñ5 m, and is based on a 19-point solution
If you use that transformation, the epoch date is meaningless. If you've got more accurate control points in NAD27, then a least squares-based derivation could work to maintain accuracy.
FWIW,
Anyone wondering how one might use the translations provided by MKennedy above to derive an NAD27 geographic coordinate from WGS84 geographic coordinates should refer to:?ÿ http://www.ihsenergy.com/epsg/guid7_2.pdf pages 81 and 82. The guide helpfully provides an example with an answer. There is a table in the document showing NAD27 ellipsoid parameter (Clarke 1866) that are not used in the example.?ÿ
WGS84 parameters you??ll need are: a = 6378206.4 and the inverse of flattening (1/f) is 294.97870. You will use flattening in the computation.
This is the Abridged Molodensky transformation.
Have fun!
DMM
